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At least 199 records · Page 11Linked to original sources

Congenitally missing mandibular second premolars: clinical options.

INTRODUCTION: Congenital absence of mandibular second premolars affects many orthodontic patients. The orthodontist must make the proper decision at the appropriate time regarding management of the edentulous space. These spaces can be closed or left open. IMPLICATIONS: If the space will be left open for an eventual restoration, the keys during orthodontic treatment are to create the correct amount of space and to leave the alveolar ridge in an ideal condition for a future restoration. If the space will be closed, the clinician must avoid any detrimental alterations to the occlusion and the facial profile. SIGNIFICANCE: Some early decisions that the orthodontist makes for a patient whose mandibular second premolars are congenitally missing will affect his or her dental health for a lifetime. Therefore, the correct decision must be made at the appropriate time. PURPOSE: In this article, we present and discuss various treatment alternatives for managing orthodontic patients with at least 1 congenitally missing mandibular second premolar.

Adolescent↗

Antilymphoid antibody preconditioning and tacrolimus monotherapy for pediatric kidney transplantation.

OBJECTIVE: Heavy post-transplant immunosuppression may contribute to long-term immunosuppression dependence by subverting tolerogenic mechanisms; thus, we sought to determine if this undesirable consequence could be mitigated by pretransplant lymphoid depletion and minimalistic post-transplant monotherapy. STUDY DESIGN: Lymphoid depletion in 17 unselected pediatric recipients of live (n = 14) or deceased donor kidneys (n = 3) was accomplished with antithymocyte globulin (ATG) (n = 8) or alemtuzumab (n = 9). Tacrolimus was begun post-transplantation with subsequent lengthening of intervals between doses (spaced weaning). Maintenance immunosuppression, morbidity, graft function, and patient/graft survival were collated. RESULTS: Steroids were added temporarily to treat rejection in two patients (both ATG subgroup) or to treat hemolytic anemia in two others. After 16 to 31 months (mean 22), patient and graft survival was 100% and 94%, respectively. The only graft loss was in a nonweaned noncompliant recipient. In the other 16, serum creatinine was 0.85 +/- 0.35 mg/dL and creatinine clearance was 90.8 +/- 22.1 mL/1.73 m2. All 16 patients are on monotherapy (15 tacrolimus, one sirolimus), and 14 receive every other day or 3 times per week doses. There were no wound or other infections. Two patients developed insulin-dependent diabetes. CONCLUSION: The strategy of lymphoid depletion and minimum post-transplant immunosuppression appears safe and effective for pediatric kidney recipients.

Adolescent↗

Age-related changes in auditory spatial properties of the guinea pig superior colliculus.

The map of auditory space located in the deep layers of the guinea pig superior colliculus (SC) is a complex computational representation of the auditory azimuth surrounding the animal. The map undergoes a protracted developmental profile during the first postnatal month and remains plastic until well into adulthood. However, there are no data concerning the state of the collicular auditory space map in much older animals. Multi-unit responses to broadband noise stimuli presented around the azimuthal plane under anechoic conditions were recorded from the deep SC of guinea pigs of a variety of ages, up to 44 months. The data obtained show that the map remains stable up to the age of approximately 36 months. However, after this age, the map shows rapid deterioration and at 42 months, multi-unit responses did not show features consistent with a normal map. It appears that deficits accruing within the central auditory system with increasing age, combine to overcome the ability of the mechanisms of plasticity responsible for space map maintenance to keep pace with the changes, resulting in degraded SC spatial tuning with increasing age.

Aging↗

The use of the lingual arch in the mixed dentition to resolve incisor crowding.

In the mixed dentition, arch length preservation, maintaining the leeway space, can often provide adequate space to resolve lower incisor crowding. Yet the frequency of this occurrence is not known. To obtain this information, lingual arches were placed in the mandibular arches of 107 consecutive mixed dentition patients with incisor crowding to preserve arch length and make the leeway space available to resolve the crowding. Arch length decreased only 0.44 mm whereas the intercanine, interpremolar, and intermolar dimensions increased between 0.72 and 2.27 mm. There was adequate space to resolve the crowding in 65 (60%) of the 107 patients. If perfect arch length preservation had occurred, there would have been adequate space to resolve the crowding in 73 (68%) of the 107 patients. The correlation between leeway space and tooth size-arch size discrepancy was only 0.44.

Bicuspid↗

Late lower arch crowding: the effect of second molar extraction.

Mesial drift and change in crowding over a 5-year period were compared in 30 subjects whose lower second molars were extracted between ages 11 and 17 years and 30 subjects whose lower second molars were not extracted. Significant differences were found. The nonextraction subjects showed an average forward movement of first molars and an increase in crowding. The extraction group showed slight distal movement of first molars and a decrease in crowding. It is concluded that lower second molar extraction reduces the tendency to forward movement of buccal segments and increased crowding by relieving eruptive pressure from third molars and that the presence of a developing lower third molar with insufficient space can be one cause of late lower arch crowding.

Adolescent↗

Dimensions of the denture: back to basics.

The three dimensions of the denture, height, width, and length, allow tooth movements in six directions. The limitation of the tooth movements that can be accomplished is the physical environment of bone, muscle, and soft tissue. By using clinical records of more than 200 cases, each dimension of the denture was analyzed as to lateral, anterior, posterior, and vertical protraction and contraction. A study of 40 successful treatments indicated that posttreatment adjustments reflected contraction of the dentition and that protraction would not be tolerated by the dental environment of patients with normal muscular balance. A total dentition space analysis system was devised to help differentiate proper treatment strategy for all the dimensions of the denture. The space analysis emphasized the point that orthodontics is a space management procedure, and the orthodontist must become skilled in determining the space available, as well as future space increase through growth and development. Finally, guidelines were suggested for space management of all the dimensions of the dentition. These guidelines were based on an anterior, a midarch, and posterior space analysis so that the major areas of disharmony could be identified and proper space management decisions could be made.

Cephalometry↗

Leeway space and the resolution of crowding in the mixed dentition.

The leeway space provides adequate space to resolve crowding that is present in the mixed dentition in the majority of individuals. This space can be maintained by preserving arch length with a lingual arch as the primary teeth begin to exfoliate, unless conditions such as the premature loss of a primary canine require earlier intervention. A lip bumper can also be inserted after the eruption of the first premolars to preserve arch length.

Child↗

A retrospective study of 50 treatments using an appliance to produce localised occlusal space by relative axial tooth movement.

This paper describes the use of 50 appliances which have been used to produce a localised occlusal space prior to the restoration of teeth. These were provided for 45 patients aged 19 to 69 years at the Eastman Dental Hospital London between 1981 and 1994. The concept is similar to that described by Dahl, the space being produced by the teeth in contact with the appliance being intruded and those out of contact over erupting. Many of the appliances however differed from those originally described by Dahl.

Adult↗

Alternative management of a crown root fractured tooth in a child.

A crown root fracture of a tooth in a young person may necessitate the removal of the root and the placement of a space-maintaining partial denture followed by provision of a bridge. A case is reported of an alternative approach to treatment, in which the root fragment is retained in situ until the end of the pubertal growth spurt, in order to preserve alveolar bone, following which it is removed and replaced by an implant.

Child↗

The Dahl Concept: past, present and future.

The Dahl appliance was described nearly 30 years ago. This removable metal bite platform was used to create inter-occlusal space, in a localised part of the mouth, to facilitate the placement of restorations on worn anterior teeth. The Dahl concept is traditionally associated with the management of worn teeth. However, the same principles can be successfully and safely applied to a variety of clinical situations. This has simplified the management of historically complex problems. The advantages are the preservation of tooth tissue and the long-term benefits that brings. This paper reviews the literature related to the Dahl concept and how the concept has developed. There is a discussion regarding possible future applications and research.

Dental Restoration, Permanent↗